Rheostat



A. PAPINI.

aHEosT/w. APPLICATION FILED AUG.28, 1919. 1,336,918, Patented Apr. 13, i920..

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-A. PAPINI.

RHEOSTAT.

APPLICATION man AUG.28,19 |9.

1,336,918@ .Patented Apr. 13, 1920.

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MAA/Ly By l l l @Mgww UNITED sTATEs PATENT OFFICE.'

ANTONIOVPAPINI, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR TO A. MECKY COMPANY, OF PHILADELPHIA, PENNSYLVANIA, A CORPORATION OF PENN- SYLVANIA.

BHEOSTAT.

Specication of Letters Patent. A- Patented Apr. 13, 1920.

Application mea August as, 1919. serial no. 320,446.

To all whom t may concern:

Be it known that I, ANTONIO PAPINI, a subject of the King of Italy, having resided Iin the United States one year last past and having declared my intention of ecomin a citizen thereof, residing inthe city an county of Philadelphia, State of Pennsylvania, have invented a new and useful Rheostat, of which the following is a specification:

' My invention consists of a novel construction of a' rheostat which is designed to control or furnish to lamps, motors or other electric apparatus any desired amount of ,15 current from zero to the maximum available in the line, said rheostat being composed of a series of resistance elements, each one having predetermined ohmic resistance, said elements being preferably disposed in a circular or annular row, althou h it will 4be evident that they could be Vdifferently arranged and collocated if desired without departing-from the principle of my invention.

, My invention further consists of a novel 2li-construction of resistance elements each of 'which is composed of an insulating refractory shell threaded at its4 ends and secured in operative-position in any suitable manner, said shell bein filled with resistance 80 material, such as mica iakes and graphite,

or graphite and asbestos, or the like, commingled in suitable vproportions according to requirements, there being located at the bottom of said resistance material a plug of 85 conducting' material adapted to be compressed by means of a metal thimble of novel' construction, which is threaded to the lower endof said shell, the amount of the compression determining or calibratin the 40 resistance, under which the currentis a apted to drop.

It further consists of a novel collocation of resistance elements held in position by a suitable frame, com osed of top and bottom insulating plates he d in assembled position by means of bolts or the like.

It further consists of a novel construction of a control s indle of metal having a thumb lpiece of lnsulating material and provided with suitable bearings, and a metallic nger carrying at its end, a contact mem.- ber, which is at all times under tension of a suitable spring, whereby the rotation of said finger and contact member, controls or furnishes to the desired point, any amount of current, from zero to the maximum available in the line.

It further consists of a novel construction of resistance elements, -fcontact cu s therefor, and a novel manner of resilient y supporting said resistance elements.

- It further consists of other novel features of construction all as will be hereinafter fully described and in the claims.

For the urpose of illustrating my invention, I ave shown in the accompanylng drawings one form thereof which is at present preferred by me, since the same will be `found in practice to give satisfactory and reliable results, although it is to be understood that the various instrumentalities of whlch my invention consists can be variparticularly pointed out v.ously arranged and organized and that my I linvention is not limited to the precise arrangement and organization of these instru- Similar numerals of reference vindicate corresponding parts.

Referringto the drawings,

1 designates my Anovel construction of rheostat, the same comprising a suitable framework having the top and bottom insulating plates 2 andr 3, which are held in position by the bolts 4, having the upper pair of nuts 5an`d the lower'pair of nuts 6 or similar fastening devices, the bottom plate 3 being provided with legs 7, which are preferably four in number, whereby my novel device may be fastened to the Wall or floor or any other desired point. The resistance elements 8 may be of any desired number and as each element is similarly constructed, a description of one will suiiice for all.-

Each of said resistance elements is composed of a cylindrical insulating refractory shell 9 which is externally threaded at its lower and upper ends 10 and 11, respectively.

12 designates an upper thimble, which is internally threaded at its lower end so as to engage the contiguous lexteriorly threaded portion 12 of the shell 9, said thimble being of conducting material and preferably having the closed rounded top 13.

14 designates an asbestos gasket, which is interposed between the upper end of the shell 9 and the continuous wall or shoulder of the thimble 12. The shell 9 is filled with resistance material 15, which is preferably in the present instance in the form of mica flakes and graphite, or graphite and asbestos, or the like, commingled in suitable proportions. Below the resistance material 15 is the plug 16 of any suitable conducting material, which is adapted to be compressed toward, against or into the resistance material 15 by means of the lower thimble 17, which is of metal and is internally threaded to engage the lower exteriorly threaded portion 10 of the shell 9. The thimble 17 is provided with the upwardl projecting portion 18 which presses on t ebottom of the plug 16, so that it will be apparent that the amount of compression of the resistance material 15, can be predetermined or calibrated by screwing the thimble 17 on or off the 4shell 9, to the desired extent. The bottom of the thimble 17 is preferably recessed or concaved as indicated at 19 and is supported upon or in contact with the head 20 of the supporting member which has the depending stem 21 which can slide freely and has a limited play in the hole 22 of the bottom plate 3. i

23' designates a spring interposed between the top of the plate 3 and the bottom of the head 20, whereby a cushioning action is obtained, by reason of the tension of the said spring, so that a proper contact is made between. the head 20 and the recessed portiony 19 of the thimble 17.

24 designates threaded holes in the upper plate 2,- the latter being of insulating material, said threaded holes being arranged in circular order and receiving the contact c'ups 25 whose top surfaces are slightly above the top of the plate 2, so that it will be seen that when theparts are assembled, the closed top 13 of the upper thimblc 12 contacts with the underside of the contact cups 25 and that all the parts are properly and resiliently held in assembled position by the tension of the spring 23, since thefstem 21,v which said spring surrounds, is capable of a limlted movement through or with respect tothe` bottom plate 3, as will be understood from F' 1. llie contact cups 25 may be of any -desired number and are arranged circularl or annularly as will be understood from ig. 2, it being apparent that the number of said contact cups,-as well as thenumberof the resistance elements 8, can be varied and Aspring clip 29, which is in the form of a split cup and is secured to the bottom plate 3 by any suitablefastening means, as a screw 30, the head of which bears upon the bottom of said clip 29, said screw passing through the bottom plate 3 and serving as a bindingpost being held in position by a nut 3 1 or equivalent fastening device.

.32 designates a collar which is located below the bottom of the bearing 28 and is pinned tothe spindle 26 by the pin 33, so that all the parts are at all times properly retained in assembled position.

34 designates a linger of metal which is secured to the spindle 26 so as to rotate in unison therewith, the outer end of said finger having the upwardly extending stem 35 of the contact member 36 projecting therethrough, the bottom of said Contact member riding over or resting upon one or the other of the contact cups 25.

37 designates a spring having one end secured in fixed position by the screw 3S or the like upon the finger 34 while its free end 39 presses resiliently on the top of the stem 35, so that said contact member 36 is at all times under the tension of said spring 37,

.which presses it downwardly whereby the the members 2 so that the current coming from the cond ctor 40 passes through the clip 29, the spindle 26, finger 34, contact pin 36 and contact cup 25 through a resistance element 8 and'supporting member 20 to the annular washer42, and the conductor 41, tothe lamps or apparatus and Ithen back to rthe Wire or conductor 43.

When the rheostat is in position of rest, see F 1g. 2, and the diagram in Fig. 4, the Contact member `36 is on insulating material 44 but when the rheostat is in operation, the

finger 34 and its contact member are turned bythe thumb piece 27, so that said contact member` will rest on the element representinghghresistanceaslandcanthenbe' moved in the direction of the arrow seen in said diagram until it reaches the position of no resistance, indicated at 45, whereupon the current will then pass in full.

4The stroke of the finger 34l can be limitedv by means of a stop pin 47 whose'position will be best understood from Fig. 2.

' It willv be apparent from'that foregoing that Aby my novel construction, I have produced a novel rheostat which can be cheaply manufactured and will be durable, efficient and reliable and wherein all of the parts can be readily inspected for the purposes of inspection, replacement and repair, it being apparent that any of the resistanceelements 8 canv be readily 'removed from the upper and lower connections and in case it is desired to replace anyjelement or portion of the device it can be readily and expeditiously done by unskilled labor.

Thel members comprising the resistance elements 8 are all made of standard or uniform dimensions, so that the parts are interchangeable and the varying amount of resistance desired in each element is attained by screwingthe thimbles 17 on or oii" the shells 9 so as tol compress the resistance material 15'more or less according to requirements.

It' willnow be apparent that I have devi'sed a novel and useful construction of a rheostat which embodies the features of ad vantage enumerated as desirable in the statement of the invention and the above description, and while I have, in the present instance, shown and described a preferred em- .bodiment thereof which will be found in practice to give satisfactory and reliable results, it is to be understood that the same is susceptible of modification in 4various particulars without departing from the spirit or f scope of the invention or sacrificingv any of silient engagement with said contact devices.

2. vIn a rheostat, a resistance element, composed of a shell, an upper thimble thereon, resistance material in said shell, a lowerl thimble threaded to said shell, a conducting upper and lower insulating plates annularly arranged, contact cups seated in said plates,

plug contained within said shell, intermediately of said lower thimble and said resistance material, lwhereby the rotationof said lower thimble varies the resistance, a rcsilient support for said lower thimble, anda contact device for said upper thimble.

3. In a rheostat, a plurality of resistance elements annularly arranged and supported,

- ments, contact cups a ove said elements, and Aa rotatable contact member 1n resilient engagement with said contact cups.

4. In a rheostat, a framework, a plurality of resistance elements annularly arranged thereon, tension devices bearing on "the-bottom of saidelements, a rotatable spindle centrally arranged with respect to said elements, a finger carried by said spindle, a spring pressed contact member carried by said finger, and contact cups carried in said framework and alining with said resistance elements. 5. In a rheostat, a resistance elementcomposed of a shell, an upper thimble threaded thereto, resistance material in said shell, a lower thimble also threaded `to said shell, a conducting plug contained in said shell intermedi-ately of said lower thimble and said resistance, whereby the rotation of said lower thimble varies the resistance, a resilient support for said lower thimble, a contact cup engaging said upper thimble, a movable contact member for closing the circuit with respect to said resistance element, and means for resiliently pressing said contact member into contact with said contact cup. v v

.6. In a rheostat, a framework composed of upper and lower insulating plates, contact cups mounted in said plates, resistance elements having their upper ends seated in said contact cups and theirlower ends resiliently supported, a contact member movably mounted with respect to said contact cups, and resilient means -for pressing said -contact member downwardly into contact with said cups.

7. In a rheostat, a framework composed of upper and lowernonconducting plates spaced apart and supported, contact cups in said upper plate, resistance elements below said contact cups, each of said elements comprising a shell, an upper thimble in engagement therewith and in contact with its alining cup, a lower thimble having an inwardly projecting portion and in threaded engagement with its shell, resistance material in said shell, a plug intermediate said resistance material and in contact with the inwardly. projecting portion of said lower thimble, and resilient supports for said resistance'elements.

8. In a rheostat, a framework comprising resistance elementsalso annularly arranged and having their upper ends alining with -and in contact with said contact cups, re-

spindle seated therein, and a finger rotatable in unison with. said spindle and carrying a contact member adapted to contact with said contact cups;

9. In a rheostat, a framework comprising upper and lower insulating plates, contact cups seated in said 'upper plate, resistance elements having their upper ends alining with and in contact with said contact cups, resilient supporting means for the bottom ot' said resistance elements, the latter and said cups being annularly arranged, a spring clip connected to said lower plate and having a spindle seated therein, a finger located above said upper plate and rotatable in unison with said spindle and carrying a contact member movably mounted in its`-outer end, and resilient means for pressing said contact member downwardly upon the top of said contact cups.

y 10.- In a rheostat, a framework composed of upper and lower insulating plates, contact cups seated in said plates and arranged in a circle, resistance elementsin alinement with said contact cups and in contact therewith, supporting members for the bottom of said resistance elements, said supporting members having stems passing through said lower plate and provided with upper heads contacting with and supporting said resistance elements, springs intermediate said heads and bottom plate, an annular conducting washer connected to the lower ends of the circular row of supporting devices, and means for closing an electric circuit with respect to a vdesired contact cup and resistance element.

11. In a rheostat, a framework composed of upper and lower insulating plates, contacts cups seated in said plates and arranged in a circle, resistance elements in alinement with said contact cups and in contact'therewith, supporting members for the bottom of said resistance elements, said supporting members havingstems Ipassing through said bottom plate and provided with heads supporting said resistance elements, springs intermediate said heads and bottom plate, an annular conducting washer connected to the bottom ends of the circular row of supporting devices, and means for closing an electric circuit with respect to a desired contact cup and resistance element, said means comprising a spring clip secured to the lower of said plates, a spindle having its lower end rotatably `mounted in said lspring clip, a bearing for the upper portion of said spindle located in the upper of said nonconducting y plate, a finger'carried by said spindle, and

a contact member carried by sai finger.

12. In'a rheostat, a framework composed of upper and lower insulating lates, contact cupsseated in said upper plilte and arranged 'in a circle, resistance elements in alpement with `aid contact cups and in conportin tact therewith, supporting members for the bottom of said resistance elements, said supmembers having means passin 1 throug said lower plate and provided wit heads supporting said resistance elements, springs intermediate said heads and lower plate, an annular connecting washer connected to the bottom ends of the circular row of supporting devices, means for closmg an electric circuit with respect to a desired contact cup, said means comprising a spring clip secured to said lower plate, a spindle having its lower end rotatably mounted in said spring clip, a bearing for the upper end of said spindle located in said upper nonconducting plate, a finger above said upper plate and carried by said spindle, a contact member movably mounted in said finger, and resilient means for pressing said contact member downwardly upon a contact cup,

13. In a rheostat, a framework composed of upper and lower nonconducting plates suitably supported, a series of contact cups arranged in a circle and sea-ted in the top of said upper plate, an insulation element and an element of no resistance also circularly arranged in said upper plate, a series of resistance elements of varying resistance arranged in alinement with saidcontact cups, a spindle arranged in the center of said circle of resistance elements, and contact devices carried by said spindle and adapted to be moved respectively from said insulation element .to the highest resistance element and thence to the elements of lower resistance to the point of no resistance.

14. In a rheostat, a framework composed of u per and lower nonconducting plates suita ly supported, a series of contact cups arranged in a circle and seated in the top of said upper plate, an insulation element and an element-of no resistance also circularly arranged in said upper plate, a series of resistance elements of varying resistance arranged in alinement with said contact cups,

means for resiliently supporting the bottoms of said resistance elements, a spindle arranged in the center of said circle of resistance elements, and contact devices car-- ried` by said spindle and adapted to be moved respectively from said insulation elelment to the highest resistance element and thenceJ to the elements of lower resistance to the point of no resistance. y

15. In a rheostat, a framework composed -of u per and lower'nonconducting plates suita ly supported, a series of contact cups arranged in a circle in the top of said upper plate, an insulation element and an element of no resistance also circularly arranged in` resistance elements, a spindle arranged in the'center of said circle of resistance elements, contact devices carried by said spindle and adapted to be moved respectivelyv from said insulation element to the highest resistance elementthence to the elements of lower resistance to the element of no resistance, and a conducting annular Washer'se-` cured .to the lower portion of said resilient -supporting devices for said resistance elements.

16. In a rheostat, a framework 'composedof no resistance also circularly arranged in said upper plate to complete the circle of said cups, a series of resistance elements of varying resistance arranged in alinement with said Contact cups, supporting means for the bottom of said resistance elements, a spindle rotatably supported, a finger on said spindle, a contact device carried by said iinger, and a stop for said finger adapted to normally retain said contact device when inoperative upon said insulation element.

ANTONIO PAPINI. 

